System and method for platelet removal during mononuclear cell collection

ABSTRACT

A method of collecting mononuclear cells, comprising separating whole blood into cellular components and platelets suspended in plasma, separating the platelets suspended in plasma into platelet concentrate and platelet-poor plasma, combining the cellular components with the platelet-poor plasma to form a first mixture, and separating the first mixture into mononuclear cells and at least one component.

This application is a divisional of U.S. patent application Ser. No.15/693,799, filed Sep. 1, 2017, which claims the benefit of U.S.Provisional Patent App. No. 62/397,434 filed Sep. 21, 2016, each ofwhich is expressly incorporated herein by reference in its entirety.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent App. No.62/397,434 filed Sep. 21, 2016, which is expressly incorporated hereinby reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure is directed to fluid treatment systems andmethods. More particularly, the present disclosure relates to systemsand methods for separating blood into its constituents and subsequentlytreating and/or collecting the constituents.

BACKGROUND

A variety of available blood processing systems allows for thecollection and processing of particular blood components, rather thanwhole blood, from donors or patients. In the case of a blood donor,whole blood is drawn from the donor, a desired blood constituentseparated and collected, and the remaining blood components returned tothe donor. By removing only particular constituents rather than wholeblood, it takes the donor's body a shorter time period to recover tonormal blood levels, thereby increasing the frequency with which thedonor may donate blood. It is beneficial to increase in this manner theoverall supply of blood constituents made available for health care,such as red blood cells (RBCs), leukocytes, mononuclear cells (MNCs),plasma, and/or platelets, etc. In the case of a patient, whole blood issimilarly drawn from the patient, a particular blood constituent firstseparated and then collected and/or treated, and the remaining bloodcomponents returned to the patient. The collected and/or treated bloodconstituent may be saved for future use, returned to the patient, and/ordiscarded and replaced with a suitable replacement.

The separation of blood components from whole blood typically takesplace prior to the collection or treatment of the separated bloodcomponent and may be achieved through a spinning membrane orcentrifugation, in which whole blood is passed through a centrifuge ormembrane after it is withdrawn from the patient/donor. To avoidcontamination and possible infection of the patient/donor, the blood ispreferably contained within a sealed, sterile fluid flow system duringthe entire separation process. Typical blood processing systems thus mayinclude a permanent, reusable hardware assembly containing the hardware(drive system, pumps, valve actuators, programmable controller, and thelike) that pumps the blood, and a disposable, sealed and sterile fluidcircuit that is mounted in cooperation on the hardware. In the case ofseparation via centrifugation, the hardware assembly includes acentrifuge that may engage and spin a separation chamber of thedisposable fluid circuit during a blood separation step. The blood,however, may make actual contact only with the fluid circuit, whichassembly may be used only once and then discarded or used for otherpurposes. In the case of separation via a spinning membrane, adisposable single-use spinning membrane may be used in cooperation withthe hardware assembly and disposable fluid circuit.

In the case of separation via centrifugation, as the whole blood is spunby the centrifuge, the heavier (greater specific gravity) components,such as red blood cells, move radially outwardly away from the center ofrotation toward the outer or “high-G” wall of the separation chamber ofthe fluid circuit. The lighter (lower specific gravity) components, suchas plasma, migrate toward the inner or “low-G” wall of the separationchamber. Various ones of these components can be selectively removedfrom the whole blood by forming appropriately located channeling sealsand outlet ports in the separation chamber of the fluid circuit.

In the case of separation via a spinning membrane, whole blood may beprocessed within a disposable spinning membrane, rather than within aseparation chamber of a fluid circuit. Larger molecules, such as redblood cells, may be retained within one side of the membrane, while thesmaller molecules, such as plasma, may escape through the pores of themembrane to the other side of the membrane. Various ones of thesecomponents can be selectively removed from the whole blood by formingappropriately located outlet ports in the housing of the membranecolumn. Various types of membranes with different pore sizes may beused, depending on the components to be separated.

In the case of MNC collection, which includes the collection oflymphocytes, monocytes, and/or stem cells, MNCs can be removed from thewhole blood of a patient/donor, collected, and/or subjected to varioustherapies. Collected and treated MNCs may then be returned to thepatient/donor for the treatment of various blood diseases by, e.g.,eliminating immunogenicity in cells, inactivating or killing selectedcells, inactivating viruses or bacteria, reconstituting the immunesystem, and/or activating desirable immune responses. MNC treatments areused for blood or solid organ/tissue cancers, photopheresis treatments,autologous and allogeneic stem cell transplants, donor lymphocyteinfusions, research collections, etc.

SUMMARY

According to an exemplary embodiment, the present disclosure is directedto a method of collecting mononuclear cells, comprising separating wholeblood into cellular components and platelet-rich plasma, separating theplatelet-rich plasma into platelet concentrate and platelet-poor plasma,combining the cellular components with the platelet-poor plasma to forma first mixture, and separating the first mixture into mononuclear cellsand at least one component.

According to an exemplary embodiment, the present disclosure is directedto an automated system of collecting mononuclear cells, comprising adisposable fluid circuit configured to work in association with aseparator, the disposable fluid circuit comprising a plurality of fluidpathways and containers, wherein the separator is configured by acontroller to separate whole blood into cellular components andplatelet-rich plasma. The automated system also comprises a separationchamber forming a part of the disposable circuit, wherein a firstcompartment of the separation chamber is configured to receive theplatelet-rich plasma and separate the platelet-rich plasma into plateletconcentrate and platelet-poor plasma. The first compartment of theseparation chamber is configured to direct the platelet-poor plasma to asecond compartment of the separation chamber to combine with thecellular components to form a first mixture and separate the firstmixture into mononuclear cells and at least one component.

According to an exemplary embodiment, the present disclosure is directedto a method of collecting mononuclear cells, comprising separating witha separator whole blood from a whole blood source into cellularcomponents and platelet-rich plasma, returning the cellular componentsto the whole blood source, removing platelet-rich plasma to reduceplatelet concentration of whole blood flowing into the separator,separating platelet-reduced whole blood from the whole blood source intocellular components and lower concentration platelet-rich plasma, andseparating lower platelet concentration whole blood from the whole bloodsource into mononuclear cells and at least one component.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the present embodiments will becomeapparent from the following description, appended claims, and theaccompanying exemplary embodiments shown in the drawings, which arebriefly described below.

FIG. 1 is a diagrammatic depiction of a separation system useful in theseparation and collection of mononuclear cells, according to anexemplary embodiment;

FIG. 2 is a perspective view of the front panel of a separation systemwith a disposable processing set for collecting mononuclear cellsmounted on the device, according to an exemplary embodiment;

FIG. 3 is a diagram showing the disposable processing set of FIG. 2,according to an exemplary embodiment;

FIGS. 4A-4C are diagrammatic depictions illustrating a method forobtaining mononuclear cells, according to several exemplary embodiments;and

FIG. 5 is a flow diagram illustrating a method for obtaining mononuclearcells, according to an exemplary embodiment.

DETAILED DESCRIPTION

There are several aspects of the present subject matter which may beembodied separately or together in the devices and systems described andclaimed below. These aspects may be employed alone or in combinationwith other aspects of the subject matter described herein, and thedescription of these aspects together is not intended to preclude theuse of these aspects separately or the claiming of such aspectsseparately or in different combinations as set forth in the claimsappended hereto.

Some embodiments may provide for collecting MNCs with reduced plateletinterference during MNC harvest.

Some embodiments may provide for more accurate collection and harvest ofMNCs by allowing for a clearer interface between blood component layers.

During harvest of MNCs, non-target substances may be present in the MNCproduct that can interfere with efficient harvesting of the target MNCs.For example, if a donor/patient has a high platelet count and/or othercondition is present that alters platelet behavior and/or activationstate, platelets may be induced to aggregate, clump, and/or build upwithin the separator, leading to challenges in proper and efficient MNCcollection during leukapheresis. One mitigation practice has been tointroduce more anticoagulant to the system, which may result in moreanticoagulant being introduced into the patient/donor.

Some embodiments may be conducive to successful procedures beingperformed without excess anticoagulant being introduced to the systemand/or patient/donor, thereby also leading to faster procedure times andhigher collection efficiencies.

FIG. 1 is a diagrammatic depiction of a separation system 10 useful inthe separation and collection of mononuclear cells, as described herein,and FIG. 2 shows an exemplary embodiment of the separation system 10.The system 10 may include a separation component 12 and a disposableprocessing kit 14 (FIG. 2) that is mounted thereon. Flow direction andrate may be controlled by a plurality of pumps 15 engaged with theprocessing kit 14. In one embodiment, the separation principle used bythe separator 12 is based on centrifugation, but an automated separatorbased on a different separation principle (e.g., spinning membrane,etc.) may also be used.

A patient/donor may be connected to the fluid circuit 14, which mayprovide a sterile closed pathway between the separation component 12 andthe remainder of the processing kit 14. Whole blood that is withdrawnfrom the patient/donor may be introduced into the separation component12, where the whole blood may be separated to provide a target cellpopulation, which in the context of the present disclosure may bemononuclear cells. Other components separated from the whole blood, suchas red blood cells and platelets may be returned to the patient/donor orcollected in pre-attached containers of the blood processing set. Theseparated target cell population, e.g., mononuclear cells, may then becollected for future use or prepared for various therapies.

Apparatus useful in the collection of mononuclear cells, and providingthe separation component 12 of FIG. 1, include for example the Amicus®Separator made and sold by Fenwal, Inc., of Lake Zurich, Ill.Mononuclear cell collections using a device such as the Amicus® aredescribed in greater detail in U.S. Pat. No. 6,027,657, the contents ofwhich are incorporated by reference herein in its entirety. The fluidcircuit 14 (FIG. 3) may include a blood processing container 16 defininga separation chamber suitable for harvesting MNCs from whole blood.

As shown in FIG. 2, a disposable processing set or fluid circuit 14(which includes container 16) may be mounted on the front panel of theseparation component 12. The processing set (fluid circuit 14) mayinclude a plurality of processing fluid flow cassettes 23L, 23M and 23Rwith tubing loops for association with peristaltic pumps 15 on theseparation component 12. Fluid circuit 14 may also include a network oftubing and pre-connected containers for establishing flow communicationwith the patient/donor and for processing and collecting fluids andblood and blood components, as shown in greater detail in FIG. 3.

As seen in FIG. 3, the disposable processing set 14 may include acontainer 60 for supplying anticoagulant, an in-process container 62, acontainer 64 for holding a crystalloid solution, such as saline, acontainer 66 for collecting plasma, and a container 68 for collectingthe mononuclear cells.

With reference to FIG. 3, fluid circuit 14 may include inlet line 72, ananticoagulant (AC) line 74 for delivering AC from container 60, an RBCline 76 for conveying red blood cells from chamber 16 of set 14 tocontainer 67, a plasma line 78 for conveying plasma to container 66 andline 80 for conveying mononuclear cells to and from separation chamber16 and collection container 68.

The blood processing set may also include one or more venipunctureneedle(s) or access device(s) for accessing the circulatory system ofthe patient/donor. As shown in FIG. 3, fluid circuit 14 may includeinlet access device 70 and return access device 82. In an alternativeembodiment, a single access device may serve as both the inlet andoutlet access device.

Fluid flow through fluid circuit 14 may be driven, controlled andadjusted by a microprocessor-based controller in cooperation with thevalves, pumps, weight scales and sensors of separation component 12 andfluid circuit 14, the details of which are described in the previouslymentioned U.S. Pat. No. 6,027,657.

A separation chamber may be defined by the walls of the processingcontainer 16. The processing container 16 may comprise two differentcompartments 16 a and 16 b (FIG. 3). Using both compartments 16 a and 16b for separation in a procedure may enable multiple target products tobe separated simultaneously and/or multiple steps to be completedsimultaneously. If only one compartment is used for separation, theother compartment may optionally be used as an in-process, waste, orstorage container. In operation, the separation device 12 may rotate theprocessing container 16 about an axis, creating a centrifugal fieldwithin the processing container 16. Details of the mechanism forrotating the processing container 16 are disclosed in U.S. Pat. No.5,360,542 titled “Centrifuge with Separable Bowl and Spool ElementsProviding Access to the Separation Chamber,” which is also incorporatedherein by reference in its entirety.

In one embodiment, an apheresis device or system 10 may include aprogrammable controller that is pre-programmed with one or moreselectable protocols. A user/operator may select a particular processingprotocol to achieve a desired outcome or objective. The pre-programmedselectable protocol(s) may be based on one or more fixed and/oradjustable parameters. During a particular processing procedure, thepre-programmed controller may operate the separator 12 and processingchamber 16 associated therewith to separate blood into its variouscomponents, as well as operate one or more pumps to move blood, bloodcomponents and/or solutions through the various openable valves andtubing segments of a processing set, such as processing set 14illustrated in FIG. 3. The various processing steps performed by thepre-programmed automated apheresis device may occur separately, inseries, simultaneously or any combination of these.

An automated apheresis device may be used to perform MNC collection in abatch process in which MNCs continuously collect in the chamber 16 untilthe target cycle volume is reached. During the continuous collection ofMNCs within the chamber 16, different blood components separate intolayers that may be detected by an optical interface detector thatmonitors the location and presence of the interface between layers.Details of an exemplary mechanism for interface detection are disclosedin U.S. Pat. No. 6,027,657, the contents of which are incorporated byreference herein in its entirety. Before and during the transfer of theMNCs out of the chamber 16, MNCs and other blood components (e.g.,plasma, platelets, etc.) may pass through an optical sensor 17, locateddownstream of the chamber 16, which detects the presence of cells in thetubing line to determine the start and end of the MNC harvest (i.e. whento open and close the valves leading to the product container). The term“downstream” describes an event proximal to post-separation, and theterm “upstream” describes an event proximal to pre-separation.“Downstream” and “upstream” are relative terms, with the reference pointbeing the time/location of separation. After MNC harvest is complete,the remaining cells in the line may be flushed into the productcontainer with a predetermined volume of plasma known as the “plasmaflush”.

The ability of the separation chamber to efficiently harvest the MNCsmay be facilitated by removal of non-target substances (e.g., platelets)that may be present in the blood that can interfere with the separationprocedure. Additionally, the removal of non-target substances mayimprove the ability of the optical sensor 17 to accurately detect thepresence of cells in the tubing line to determine the start and end ofthe MNC harvest to facilitate precise harvesting of the target MNCs.

EXAMPLES

Without limiting any of the foregoing, the subject matter describedherein may be found in one or more methods, systems and/or products. Forexample, in one aspect of the present subject matter, an improved systemand method for obtaining MNCs is set forth in FIG. 4A. The inlet accessdevice 70 of FIG. 3 attached to inlet line 72 may first be connected toa blood source 5 (e.g., donor, patient, blood bag, etc.). Whole bloodmay enter the separation chamber 16 of the separator 12, which separatesthe whole blood into cellular components and platelets suspended inplasma. FIG. 4A shows the separation into cellular components andplatelets suspended in plasma taking place in compartment 16 a, buteither compartment 16 a or 16 b may be used. The platelets and plasma(referred to as “platelet-rich plasma”) may be separated and directedinto container 66, and the cellular components may be separated andreturned to the patient/donor via return line 82 a and access device 82(FIG. 3). An optical sensor 17 may be placed downstream of theseparation chamber 16 a or 16 b at a tubing line leading to container 66to determine when a sufficient amount of platelets has been removed andplatelet-rich plasma is clear enough for the removal of plateletssuspended in plasma into container 66 to stop.

Once a sufficient amount of non-target content (e.g., platelets) hasbeen removed into container 66, MNC collection may begin. Referring toFIG. 4A, whole blood from the blood source 5 (e.g., donor, patient,blood container, etc.) may enter the separation chamber 16 of theseparator 12 into either compartment 16 a or 16 b via the inlet needleaccess device 70 (FIG. 3) attached to inlet line 72. Within theseparation chamber 16, the separator 12 may separate the whole bloodinto lower concentration platelet-rich plasma (due to some of theplatelets having been removed earlier into container 66), MNCs, andremaining cellular components (e.g., RBCs). While MNCs continuouslycollect within the chamber 16, the lower concentration platelet-richplasma and remaining cellular components may be separated and directedback to the blood source 5 via return line 82 a and/or stored for lateruse. Upon the target amount of MNCs having been collected and remainingcellular components and lower concentration platelet-rich plasma havingbeen returned to the blood source 5 and/or stored, the collected MNCsmay be harvested into a designated container 68 to be processed forfurther treatment, and the platelets suspended in plasma in container 66used for other purposes or discarded.

In another aspect of the present subject matter, an improved system andmethod for obtaining MNCs is set forth in FIG. 4B. The inlet line 72 maybe connected to a blood source 5 (e.g., donor, patient, blood bag,etc.). Whole blood may enter the separation chamber 16 of the separator12, which separates the whole blood into cellular components andplatelet-rich plasma. FIG. 4B shows the separation into cellularcomponents and platelet-rich plasma taking place in compartment 16 a,but either compartment 16 a or 16 b may be used. The platelet-richplasma may be separated and directed into in-process container 62, andthe cellular components may be separated and returned to thepatient/donor via return line 82 a. When all cellular components haveleft the separation chamber 16, the platelet-rich plasma in in-processcontainer 62 may be directed back into the separation chamber 16 (intoeither compartment 16 a or 16 b) to be separated into plasma andplatelet concentrate. The platelet concentrate may be directed tocontainer 66 or another container to be discarded or used for otherpurposes, and the separated plasma may be returned to the blood source 5via return line 82 a and/or stored for later use.

Once a sufficient amount of non-target content (e.g., platelets) hasbeen removed into container 66, MNC collection may begin. Referring toFIG. 4B, whole blood from the blood source 5 (e.g., donor, patient,blood bag, etc.) may enter the separation chamber 16 of the separator 12into either compartment 16 a or 16 b via the inlet line 72. Within theseparation chamber 16, the separator 12 may separate the whole bloodinto lower concentration platelet-rich plasma (due to some of theplatelets having been removed earlier into container 66), MNCs, andremaining cellular components (e.g., RBCs). While MNCs continuouslycollect within the chamber 16, the lower concentration platelet-richplasma and remaining cellular components may be separated and directedback to the blood source 5 via return line 82 a and/or stored for lateruse. Upon the target amount of MNCs having been collected and remainingcellular components and lower concentration platelet-rich plasma havingbeen returned to the blood source 5 and/or stored, the collected MNCsmay be harvested into a designated container 68 to be processed forfurther treatment.

The process and steps of whole blood initially being separated intocellular components and platelet-rich plasma and the platelet-richplasma being separated into platelet concentrate and plasma portrayed inFIG. 4B may take place substantially in series if only one compartment16 a or 16 b is utilized. In another aspect of the present subjectmatter, a system and method for obtaining MNCs is set forth in FIG. 4C,in which the process and steps of whole blood initially being separatedinto cellular components and platelet-rich plasma and the platelet-richplasma being separated into platelet concentrate and plasma may takeplace substantially at the same time when both compartments 16 a and 16b are utilized. Turning to FIG. 4C, the inlet line 72 may be connectedto a blood source 5 (e.g., donor, patient, blood bag, etc.). Whole bloodmay enter the separation chamber 16 of the separator 12 at a firstcompartment, e.g., compartment 16 a, where whole blood may be separatedinto cellular components and platelet-rich plasma. The platelet-richplasma may be directed into a second compartment, e.g., compartment 16b, of the separation chamber 16, and the cellular components may beseparated and returned to the blood source 5 via return line 82 a.Substantially at the same time that the whole blood is being separatedin compartment 16 a into cellular components and platelet-rich plasma,the platelet-rich plasma directed to compartment 16 b may be separatedinto plasma and platelet concentrate within compartment 16 b. Theseparated plasma may be returned to the blood source 5 via return line82 a and/or stored for later use. The platelet concentrate may bedirected to container 66 or another container to be discarded or usedfor other purposes, or may remain within compartment 16 b. An opticalsensor 17 may be placed downstream of the first compartment 16 a todetermine when a sufficient amount of platelets has been removed andplatelet-rich plasma is clear enough for the separation of plasma andplatelet concentrate in the second compartment 16 b to stop.

Once a sufficient amount of non-target content (e.g., platelets) hasbeen removed and/or interference with separation is minimized, MNCcollection may begin. Referring to FIG. 4C, whole blood from the bloodsource 5 (e.g., donor, patient, blood bag, etc.) may enter theseparation chamber 16 of the separator 12 into either compartment 16 aor 16 b via the inlet line 72. If the platelet concentrate has been leftto recirculate and remain within a compartment in the previous step, thewhole blood may be directed to the compartment that does not contain theplatelet concentrate, e.g., compartment 16 a. Within compartment 16 a ofseparation chamber 16, the separator 12 may separate the whole bloodinto lower concentration platelet-rich plasma (due to some of theplatelets having been removed earlier in compartment 16 b), MNCs, andremaining cellular components (e.g., RBCs). While MNCs continuouslycollect within compartment 16 a of separation chamber 16, the lowerconcentration platelet-rich plasma and remaining cellular components maybe separated and directed back to the blood source 5 via return line 82a and/or stored for later use. Upon the target amount of MNCs havingbeen collected and remaining cellular components and lower concentrationplatelet-rich plasma having been returned to the blood source 5 and/orstored, the collected MNCs may be harvested into a designated container68 to be processed for further treatment.

In another aspect of the present subject matter, a method for obtainingMNCs is set forth in FIG. 5. An inlet access device or connector mayfirst be connected to a blood source 5 (e.g., donor, patient, blood bag,etc.) at step 100 of FIG. 5. At step 200, whole blood enters aseparator, which separates the whole blood into cellular components(step 301) and platelet-rich plasma (step 302). In the embodiment inFIG. 5, the separator of step 200 may be a centrifugal or spinningmembrane separator. An exemplary spinning membrane and hardware isdisclosed in greater detail in PCT Patent Application No.PCT/US2012/28492, which is incorporated herein by reference in itsentirety, although any suitable membrane assembly may be used. Cellularcomponents separated at step 301 may be returned to the blood source 5.Platelet-rich plasma separated at step 302 may be discarded or used forother purposes at step 401 or be further separated into plateletconcentrate (step 402 b) and plasma (step 402 a). The plateletconcentrate may be discarded or used for other purposes (step 403), andthe plasma may return to the blood source 5.

At step 500, when an adequate amount of non-target content (e.g.,platelets) has been removed and/or interference with separation isminimized, MNC collection may begin. The separator may separate wholeblood having reduced platelets into plasma, MNCs and remaining cellularcomponents. The MNCs may be harvested at the end of the procedure atstep 602, and the plasma and remaining cellular components may bereturned to the blood source or collected at step 601.

The embodiments disclosed herein are for the purpose of providing adescription of the present subject matter, and it is understood that thesubject matter may be embodied in various other forms and combinationsnot shown in detail. Therefore, specific embodiments and featuresdisclosed herein are not to be interpreted as limiting the subjectmatter as defined in the accompanying claims.

The invention claimed is:
 1. A method of collecting mononuclear cells,comprising: separating with a separator whole blood from a whole bloodsource into cellular components and platelet-rich plasma; removing thecellular blood components and the platelet-rich plasma from theseparator; returning the cellular components to the whole blood sourcewithout returning at least a portion of the platelets in theplatelet-rich plasma to the whole blood source to reduce plateletconcentration of whole blood subsequently flowing into the separatorfrom the whole blood source; and separating lower platelet concentrationwhole blood from the whole blood source into mononuclear cells and atleast one component.
 2. The method of claim 1, further comprisingstopping the separation of whole blood from the whole blood source intocellular components and platelet-rich plasma when an optical sensordisposed downstream of the separator detects that the platelet-richplasma removed from the separator has a target platelet concentration.3. The method of claim 1, wherein the separator comprises a spinningmembrane separator.
 4. The method of claim 1, wherein the separatorcomprises a centrifugal separator.
 5. The method of claim 1, whereinsaid separating whole blood into cellular components and platelet-rich,plasma and said separating lower platelet concentration whole blood intomononuclear cells and at least one component are performed substantiallyin series.
 6. The method of claim 1, wherein said separating lowerplatelet concentration whole blood from the whole blood source intomononuclear cells and at least one component includes separating thelower platelet concentration whole blood into mononuclear cells, aprimarily plasma component, and remaining cellular components.
 7. Themethod of claim 1, further comprising returning the platelet-rich plasmato the separator, separating the platelet-rich plasma in the separatorinto platelet-poor plasma and platelet concentrate, and removing theplatelet-poor plasma from the separator.
 8. The method of claim 7,further comprising returning the platelet-poor plasma to the whole bloodsource without returning the platelet concentrate to the whole bloodsource.
 9. The method of claim 7, wherein said separating whole bloodinto cellular components and platelet-rich plasma and said separatingthe platelet-rich plasma into platelet-poor plasma and plateletconcentrate are performed substantially in series.
 10. The method ofclaim 7, wherein said separating whole blood into cellular componentsand platelet-rich plasma and said separating the platelet-rich plasmainto platelet-poor plasma and platelet concentrate are performedsubstantially at the same time.
 11. A blood separation system,comprising: a separator including a controller; and a disposable fluidcircuit configured to work in association with the separator, whereinthe controller is configured to control the separator to separate wholeblood from a whole blood source into cellular components andplatelet-rich plasma, remove the cellular blood components and theplatelet-rich plasma from the separator, return the cellular bloodcomponents to the whole blood source without returning at least aportion of the platelets in the platelet-rich plasma to the whole bloodsource to reduce platelet concentration of whole blood subsequentlyflowing into the separator from the whole blood source, and separatelower platelet concentration whole blood from the whole blood sourceinto mononuclear cells and at least one component.
 12. The bloodseparation system of claim 11, further comprising an optical sensordisposed downstream of the separator, wherein the controller isconfigured to stop separation of whole blood from the whole blood sourceinto cellular components and platelet-rich plasma when the opticalsensor detects that the platelet-rich plasma removed from the separatorhas a target platelet concentration.
 13. The blood separation system ofclaim 11, wherein the separator comprises a spinning membrane separator.14. The blood separation system of claim 11, wherein the separatorcomprises a centrifugal separator.
 15. The blood separation system ofclaim 11, wherein the controller is configured to control the separatorto separate whole blood into cellular component and platelet-rich plasmaand to separate lower platelet concentration whole blood intomononuclear cells and at least one component substantially in series.16. The blood separation system of claim 11, wherein the controller isconfigured to control the separator to separate lower plateletconcentration whole blood from the whole blood source into mononuclearcells and at least one component by separating the lower plateletconcentration whole blood into mononuclear cells, a primarily plasmacomponent, and remaining cellular components.
 17. The blood separationsystem of claim 11, wherein the controller is configured to control theseparator to return the platelet-rich plasma to the separator, separatethe platelet-rich plasma in the separator into platelet-poor plasma andplatelet concentrate, and remove the platelet-poor plasma from theseparator.
 18. The blood separation system of claim 17, wherein thecontroller is configured to control the separator to return theplatelet-poor plasma to the whole blood source without returning theplatelet concentrate to the whole blood source.
 19. The blood separationsystem of claim 17, wherein the controller is configured to control theseparator to separate whole blood into cellular components andplatelet-rich plasma and to separate the platelet-rich plasma intoplatelet-poor plasma and platelet concentrate substantially in series.20. The blood separation system of claim 17, wherein the controller isconfigured to control the separator to separate whole blood intocellular components and platelet-rich plasma and to separate theplatelet-rich plasma into platelet-poor plasma and platelet concentratesubstantially at the same time.